Design and Analysis of Wind Turbine Generator Power Control

The pitch control system is easy to implement, but the response is slow and output power variation is large. The aerodynamic power control for the variable speed wind turbine can limit the power into the turbine by reducing the angle of the blades. The pitch control has a large response time. Therefore, fast torque changes caused by wind gusts will affect the generator. The speed range of the generator is depending on the converter voltage and the load situation. A higher voltage available for the converter in the rotor circuit, will give a higher range of speed. A speed was chosen to make the generator choose the mechanical speed, which gives the best power output related to the wind speed. A rate limiter was chosen to avoid fast changes in the mechanical speed. The scaling of the converter could be investigated and compared with the winding ratio of the machine, to find the optimal winding ratio compared with bus voltage in the converter. The response time is mainly dictated by the hydraulic actuator, which limits the performance of the system. The controller should be used in conjunction with the pitch control system to avoid large losses during steady state operation.